I just stumbled upon a great article "Android performance case study" by Romain Guy about how you can measure and improve your Android app's performance. A very interesting reading, I already knew about some of the tools, but some were new to me. I strongly recommend it to all Android developers.
I used method profiling in the past to explore some problem areas and managed to significantly reduce CPU usage by PhoneSchedule. What tools do you use to measure your app's performance? What performance improvement tips and tricks have you discovered?